Locking chuck jaws

ABSTRACT

A jaw for use in a drill chuck having a longitudinal center axis, comprising a chuck body which includes a jaw face formed on an inner surface of the chuck body and a plurality of teeth formed on an outer surface of the chuck body, the jaw face being substantially parallel to the longitudinal center axis. A ridge depends inwardly from the jaw face toward the longitudinal center axis. The ridge includes a tool engaging surface that is substantially parallel to the longitudinal center axis and has a width of between 0.020 to 0.060 inches.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.12/212,138, filed Sep. 17, 2008, now U.S. Pat. No. 8,376,371, the entiredisclosure of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates generally to chucks for use with drills orwith electric or pneumatic power drivers. More particularly, the presentinvention relates to jaws for use with such chucks.

Both hand and electric or pneumatic tool drivers are well known.Although twist drills are the most common tools on such drivers, thetools may also comprise screw drivers, nut drivers, burrs, mountedgrinding stones, and other cutting or abrading tools. Since the toolshanks may be of varying diameter or of polygonal cross section, thedevice is usually provided with a chuck adjustable over a relativelywide range. The chuck may be attached to the driver by a threaded ortapered bore.

A variety of chucks have been developed in the art. In an oblique jawedchuck, a chuck body includes three passageways disposed approximately120° apart from each other. The passageways are configured so that theircenter lines meet at a point along the chuck axis forward of the chuck.The passageways constrain three jaws which are moveable in thepassageways to grip a cylindrical or polygonal tool shank displacedapproximately along the chuck center axis. The chuck includes a nut thatrotates about the chuck center and that engages threads on the jaws sothat rotation of the nut moves the jaws in either direction within thepassageways. The body is attached onto the drive shaft of a driver andis configured so that rotation of the body in one direction with respectto the nut forces the jaws into gripping relationship with the toolshank, while rotation in the opposite direction releases the grippingrelationship. The chuck may be keyless if it is rotated by hand.Examples of such chucks are disclosed in U.S. Pat. Nos. 5,125,673 and5,193,824, commonly assigned to the present assignee and the entiredisclosures of which are incorporated by reference herein. Variousconfigurations of keyless chucks are known in the art and are desirablefor a variety of applications.

As noted above, drill bits typically have shanks that are eithercylindrical or of a polygonal cross section. Typically, for thoseapplications wherein a large diameter accessory on the end of the drillbit is required, the drill bit shank will be of a polygonal crosssection to help provide a more secure hold of the drill bit by the jawsof the chuck. For example, self-feeding drill bits and drill bits usedto create conduits through joists for piping and electrical wiring oftenhave polygonal shanks.

A typical jaw face configuration for holding such drill bits in astandard quarter-inch chuck is shown in FIG. 1. Each jaw face includesone or more teeth that meet at a pointed apex for engaging a flatsidewall 53 of the polygonal drill bit shank 51. During drillingoperations, it is possible for torque exerted on the drill bit to causeshank 51 to work back and forth within the jaws, thereby developing alooseness. Continued drilling operations in this condition often leadsto the apexes of the jaw teeth disrupting material on the shank of thedrill bit. Eventually, the shank of the drill bit is destroyed and thedrill bit can no longer be used.

Another known jaw face configuration is shown in FIG. 2. In order toprevent damage to shank 51 of the drill bit, each jaw face is planarover the width of the corresponding sidewall 53 it engages. As such, thejaw face does not disrupt the material of the shank. However, becausethe width of each jaw face is approximately equal to the width of thecorresponding shank sidewall, during drilling operations, it is notuncommon for the torque exerted on the drill bit to cause the jaws torotate within their respective jaw passageways. Such rotation may causethe jaws to become so tight on shank 51 of the drill bit that the usercannot loosen the chuck without excessive force.

The present invention recognizes and addresses the foregoingconsiderations, and others, of prior art constructions and methods.

SUMMARY OF THE INVENTION

One embodiment of the present invention provides a jaw for use in adrill chuck having a longitudinal center axis, including a chuck bodyhaving a jaw face formed on an inner surface of the chuck body and aplurality of teeth formed on an outer surface of the chuck body. The jawface is substantially parallel to the longitudinal center axis and aridge depends inwardly from the jaw face toward the longitudinal centeraxis. The ridge includes a tool engaging surface that is substantiallyparallel to the longitudinal center axis and has a width of between0.020 to 0.060 inches.

Another embodiment of the present invention provides a jaw for use in adrill chuck having a longitudinal center axis, including a chuck bodyhaving a jaw face formed on an inner surface of the chuck body and aplurality of teeth formed on an outer surface of the chuck body. The jawface is substantially parallel to the longitudinal center axis and aridge depends inwardly from the jaw face toward the longitudinal centeraxis. The ridge includes a tool engaging surface that is planar and isparallel to the longitudinal center axis.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one embodiment of the inventionand, together with the description, serve to explain the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof to one of ordinary skill in the art, is set forth moreparticularly in the remainder of the specification, which makesreference to the accompanying figures, in which:

FIG. 1 is a cross-sectional view of a set of prior art jaws engaging ashank of a drill bit;

FIG. 2 is a cross-sectional view of a set of prior art jaws engaging ashank of a drill bit;

FIG. 3 is a longitudinal view, partly in section, of a chuck including aplurality of jaws in accordance with an embodiment of the presentinvention;

FIG. 4 is an exploded view of the chuck as shown in FIG. 3;

FIG. 5 is a side view of the plurality of chuck jaws of the chuck asshown in FIG. 3, engaging a shank of a drill bit;

FIG. 6 is a perspective view of the chuck jaw of the chuck as shown inFIG. 3;

FIGS. 7A, 7B and 7C are a front, a side and a cross-sectional view,taken along line 7C-7C of FIG. 7A, of the chuck jaw of the chuck asshown in FIG. 3;

FIG. 8 is a cross-sectional view of the plurality of chuck jaws of thechuck as shown in FIG. 3,

FIG. 9 is a cross-sectional view of the plurality of chucks engaging theshank, a drill bit, taken along line 9-9 of FIG. 5;

FIG. 10 is an exploded view of the bearing and nut of the chuck as shownin FIG. 3;

FIG. 11A is a partial perspective view of the sleeve of the chuck asshown in FIG. 3;

FIG. 11B is a partial perspective view of the bearing and sleeve of thechuck as shown in FIG. 3;

FIG. 11C is a partial perspective view of the bearing and sleeve of thechuck as shown in FIG. 3;

FIG. 12 is an exploded view of an alternate embodiment of a chuckincluding a plurality of jaws in accordance with an embodiment of thepresent invention; and

FIG. 13 is an alternate embodiment of a jaw chuck in accordance with thepresent invention.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to presently preferred embodimentsof the invention, one or more examples of which are illustrated in theaccompanying drawings. Each example is provided by way of explanation ofthe invention, not limitation of the invention. In fact, it will beapparent to those skilled in the art that modifications and variationscan be made in the present invention without departing from the scope orspirit thereof. For instance, features illustrated or described as partof one embodiment may be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents

Referring to FIGS. 3 and 4, a chuck 10 includes a body 14, a nut 16, afront sleeve 18, a nose piece 20 and a plurality of jaws 22. Body 14 isgenerally cylindrical in shape and comprises a nose or forward section24 and a tail or rearward section 26. Nose section 24 has a front face28 transverse to the longitudinal center axis 30 of body 14 and atapered surface 32 at its forward end. The nose section defines an axialbore 34 that is dimensioned somewhat larger than the largest tool shankthat the tool is designed to accommodate. A threaded bore 36 is formedin tail section 26 and is of a standard size to mate with the driveshaft of a powered or hand driver (not shown). The bores 34, 36 maycommunicate at a central region 38 of body 14. While a threaded bore 36is illustrated, such bore could be replaced with a tapered bore of astandard size to mate with a tapered drive shaft. Furthermore, body 14may be formed integrally with the drive shaft.

Body 14 defines three passageways 40 to accommodate three jaws 22. Eachjaw is separated from the adjacent jaw by an arc of approximately 120°.The axes of passageways 40 and jaws 22 are angled with respect to thechuck center axis 30 such that each passageway axis travels throughaxial bore 34 and intersects axis 30 at a common point ahead of thechuck body. The jaws form a grip that moves radially toward and awayfrom the chuck axis to grip a shank 51 of a tool, as shown in FIG. 5.

As best seen in FIGS. 5 through 8, each jaw 22 has a substantiallyplanar face 42 that is generally parallel to central axis 30 of chuckbody 14. Threads 44 are formed on the jaws opposite or outer surface,and may be constructed in any suitable type and pitch. A ridge 45depends outwardly from, and extends along, face 42 of each jaw 22. Inthe preferred embodiments shown, ridge 45 is symmetrical about a centralsymmetry plane 41 of jaw 22, wherein the central symmetry planes of eachjaw 22 intersect along longitudinal center axis 30 of chuck body 14.Each ridge 45 includes a substantially planar tool engaging surface 43that is parallel to the longitudinal center axis of chuck body 14. Forthe preferred embodiment shown, in which the plurality of jaws 22 isused in a quarter-inch drill chuck for receiving quarter-inch or lessdrill bits, the width (w) of each tool engaging surface 43 is from 0.020to 0.060 inches and the height (h) is within the range of 0.010 to 0.030inches. Most preferably, the width (w) of tool engaging surface 43 ofeach jaw 22 is approximately 0.032 inches, and the height approximately0.010 inches, when the jaws are used to secure a shank 51 of aquarter-inch or less drill bit. As best seen in FIG. 9, the toolengaging surfaces 43 of the disclosed jaws 22 are more narrow than thecorresponding sides 53 of the polygonaly shaped shank 51 of the secureddrill bit. As such, the width (w) of the tool engaging surfaces assistsin preventing the disruption of the material of shank 51, while at thesame time helps reduce the likelihood that the jaws will be adverselyrotated within their corresponding passageways.

As illustrated in FIGS. 3 and 4, body 14 includes a thrust ring 46 that,in a preferred embodiment, may be integral with the body. It should beunderstood, however, that thrust ring 46 and body 14 may be separatecomponents. Thrust ring 46 includes a plurality of jaw guideways 48formed around its circumference to permit retraction of jaws 22therethrough and also includes a ledge portion 50 to receive a bearingassembly as described below. Ledge portion 50 includes a first surface47 and a second surface 49. First surface 47 extends radially outwardly,and is perpendicular to, longitudinal center axis 30 of the chuck body.Second surface 49 extends axially along, and is concentric about,longitudinal center axis 30 of the chuck body.

Body tail section 26 includes a knurled surface 54 that receives anoptional rear sleeve 12 in a press fit at 55. Rear sleeve 12 could alsobe retained by press fit without knurling, by use of a key or bycrimping, staking, riveting, threading or any other suitable securingmechanism. Further, the chuck may be constructed with a single sleevehaving no rear sleeve.

Nose piece 20 retains nut 16 against forward axial movement. The nosepiece is press fit to body nose section 24. It should be understood,however, that other methods of axially securing the nut on the body maybe used. For example, the nut may be a two-piece nut held on the bodywithin a circumferential groove on the outer circumference of the body.Nose piece 20 may be coated with a non-ferrous metallic coating toprevent rust and to enhance its appearance. Examples of suitablecoatings include zinc or nickel, although it should be appreciated thatany suitable coating could be utilized.

The outer circumferential surface of front sleeve 18 may be knurled ormay be provided with longitudinal ribs 77 or other protrusions to enablethe operator to grip it securely. In like manner, the circumferentialsurface of rear sleeve 12, if employed, may be knurled or ribbed as at79 if desired.

Front sleeve 18 is secured from movement in the forward axial directionby an annular shoulder 91 on nose piece 20. A frustoconical section 95at the rearward end of the nose piece facilitates movement of jaws 22within the chuck.

The front and rear sleeves may be molded or otherwise fabricated from astructural plastic such as polycarbonate, a filled polypropylene, forexample a glass filled polypropylene, or a blend of structural plasticmaterials. Other composite materials such as, for example, graphitefilled polymerics may also be suitable in certain environments. Asshould be appreciated by one skilled in the art, the materials fromwhich the chuck of the present invention are fabricated will depend onthe end use of the chuck, and the above materials are provided by way ofexample only.

Nut 16 has threads 56 for mating with jaw threads 44. Nut 16 ispositioned about the body in engagement with the jaw threads so thatwhen the nut is rotated with respect to body 14, the jaws will beadvanced or retracted depending on the nut's rotational direction.

As illustrated in FIG. 10, the nut's forward axial face includesrecesses 62 that receive respective drive dogs 64 (FIG. 4) extendingfrom the inner surface of front sleeve 18. The angular width of thedrive dogs is less than that of the recesses, resulting in a slightrange of relative rotational movement, for example between 6° and 10°,between the nut and the front sleeve.

Nut 16 also defines a plurality of grooves formed as flats 68 about thenut's outer circumference. Flats 68 receive respective tabs 70 extendingforward from an inner race 72 of a bearing assembly 74. The engagementof tabs 70 and flats 68 rotationally fix the inner race to the nut,although it should be understood that there may be a slight rotationaltolerance between the two.

Inner race 72 receives a plurality of bearing elements 76, in this casebearing balls, 76 disposed between it and an outer race 78 seated onthrust ring ledge 50 (FIG. 1). Outer race 78 is rotationally fixed tobody 14 by a plurality of tabs 80 that extend inwardly from an innerperiphery 81 of outer race 78. The plurality of tabs 80 is received incorresponding grooves 82 defined by second surface 49 of the thrust ringledge 50.

Outer race 78 also includes a ratchet. In the illustrated embodiment,the ratchet is formed by a plurality of sawtooth-shaped teeth 84disposed about the inner circumferential surface of the outer race. Afirst pawl 86 extends from one side of each tab 70 and is biasedradially outward from the inner race, thereby urging a distal end 88 ofeach pawl 86 toward the outer race ratchet.

Each tooth 84 has a first side with a slope approaching 90°. The secondside has a lesser slope. Pawl 86 is defectable and is generally disposedin alignment with the slope of the second side. Thus, rotation of innerrace 72 in a direction 90 with respect to outer race 78 moves pawldistal ends 88 repeatedly over teeth 84, causing a clicking sound asends 88 fall against each subsequent tooth's second side. Thisconfiguration of teeth 84 and pawl 86, however, prevents the innerrace's rotation in an opposite direction 92. Application of rotationalforce to the inner race in this direction forces distal ends 88 into thesteep-sloped first sides of teeth 84. Since pawl 86 is generallyperpendicular to the first sides, it does not deflect inward to permitrotation.

As discussed below, direction 90 corresponds to the chuck's closingdirection, while direction 92 corresponds to the chuck's openingdirection. Accordingly, when pawls 86 engage ratchet teeth 84, the teethpermit the inner race's movement in the chuck's closing direction butprevent its movement in the opening direction.

A second deflectable pawl 94 extends to the other side of each tab 70.Like pawls 86, each pawl 94 is biased radially outward. Unlike pawls 86,however, pawls 94 do not engage the outer race ratchet.

Pawls 86 and 94 include tabs 96 and 98 at their distal ends,respectively. Referring also to FIG. 11A, an inner circumferentialsurface of sleeve 18 defines first and second recesses 100 and 102.During the chuck's operation, each tab 98 is received in one of theserecesses, depending on the sleeve's rotational position with respect tothe nut as discussed in more detail below. The sleeve also defines athird recess 104 and a cam surface 106. Also depending on the sleeve'srotational position, each tab 96 is received either by the cam surfaceor by recess 104. The sleeve includes a pair of recesses 100, 102 foreach tab 98 and a recess 104 and cam surface 106 for each tab 96.

FIG. 11C illustrates the disposition of pawls 86 and 94 when sleeve 18is in a first of two positions with respect to nut 16 (FIG. 4), whileFIG. 11B illustrates these components when the sleeve is in a secondposition with respect to the nut. For ease of illustration, both figuresomit the nut. However, referring to FIG. 4 and to the sleeve's secondposition as shown in FIG. 11B, each drive dog 64 is disposed against oradjacent to a side 108 of the gap 62 in which is it received. Each ofthe sleeve's recesses 102 receives tab 98 of one of the pawls 94, andeach recess 104 receives tab 96 of one of the pawls 86. Accordingly, thedistal end 88 of each pawl 86 engages ratchet teeth 84, and inner race72 can rotate only in direction 90 with respect to outer race 78.

Referring now to FIG. 11C, when inner race 72 moves in opening direction92 with respect to the outer race, each tab 98 moves out of its recess102 and into its recess 100, as indicated by arrow 108. Each tab 96rides up and out of its recess 104 onto its cam surface 106, asindicated by arrow 110. As indicated by arrow 112, this pushes eachdeflectable tab 86 radially inward, thereby disengaging distal ends 88from ratchet teeth 84. Thus, the inner race is free to rotate withrespect to the outer race.

As described in more detail below, when sleeve 18 rotates in direction92 so that the inner race moves from the position shown in FIG. 11B tothe position shown in FIG. 11C, drive dogs 64 move within grooves 62 ofnut 16 (FIG. 4) so that each drive dog is against or immediatelyadjacent to a side 110 of the groove.

In operation, and referring to FIGS. 4, 10, 11B and 11C, nut grooves 62receive drive dogs 64 when the chuck is between fully opened and fullyclosed positions so that the drive dogs are adjacent groove sides 110.Inner race 72 is disposed with respect to outer race 78 so that tabs 96and 98 are received by cam surface 106 and recess 100, respectively.That is, sleeve 18 is in the first position with respect to the nut. Inthis condition, tabs 98 and recesses 100 rotationally fix inner race 72to sleeve 18. Since inner race 72 is rotationally fixed to nut 16 bytabs 70 and flats 68, an operator rotating sleeve 18 rotationally drivesthe nut through inner race 72, thereby opening or closing the jaws. Whenthe operator rotates the sleeve/bearing inner race/nut in the closingdirection (indicated by arrow 90 in FIG. 10) to the point that the toolengaging surfaces 43 of the jaws tighten onto a tool shank, as shown inFIG. 9, the nut is urged rearward up the jaw threads, thereby pushingthe nut against inner race 72, bearing elements 76, outer race 78 andthrust ring 46. The rearward force creates a frictional lock between thenut and inner race 72 that further rotationally fixes two components.

The wedge between the nut threads and the jaw threads increasinglyresists the nut's rotation. When the operator continues to rotate sleeve18, and the resistance overcomes the hold provided by tabs 98 inrecesses 100, sleeve 18 rotates with respect to nut 16 and inner bearingrace 72. This moves drive dogs 64 from sides 110 of grooves 62 to sides108 and pushes tabs 98 out of recesses 100 into recesses 102.Simultaneously, cam surfaces 106 rotate away from tabs 96 so that thetabs are released into recesses 104, thereby engaging distal ends 88 ofpawls 86 with ratchet teeth 84, as shown in FIG. 11B. At this point,inner race 72, and therefore nut 16, is rotationally locked to outerrace 78, and therefore body 14, against rotation in the chuck's openingdirection. That is, the nut is rotationally locked to the chuck body inthe opening direction. Since the nut's rotation with respect to the bodyis necessary to open the chuck, this prevents inadvertent opening duringuse.

Inner race 72, and therefore nut 16, may, however, still rotate withrespect to outer race 78, and therefore body 14, in the chuck's closingdirection. During such rotation, sleeve 18 drives nut 16 through drivedogs 64 against groove sides 108, as well as through inner race 72. Thiscontinues to tighten the chuck and, as described above, produces aclicking sound to notify the operator that the chuck is in a fullytightened position.

To open the chuck, the operator rotates sleeve 18 in the oppositedirection. Sleeve 18 transfers this torque to inner race 72 at theengagement of tabs 96 and 98 in recesses 104 and 102, respectively.Because pawls 86 engage outer race 78, which is rotationally fixed tothe body, through the ratchet teeth, the inner race cannot rotate withthe sleeve. Thus, upon application of sufficient torque in the openingdirection, sleeve 18 moves with respect to the inner race and the nut.This moves tabs 96 back up onto cam surfaces 106, thereby disengagingpawls 86 from ratchet teeth 84. Tabs 98 move from recesses 102 intorecesses 100, and drive dogs 64 move from sides 108 to sides 110 ofgrooves 62. Thus, the sleeve moves to its first position with respect tothe nut, as shown in FIG. 11C, and the inner race and nut, are free torotate with respect to the outer race and chuck body. Accordingly,further rotation of sleeve 18 in the opening direction moves toolengaging surfaces 43 of jaws 22 away from the chuck axis, therebyopening the chuck.

Referring now to FIG. 12, chuck 10 is shown with alternate embodiment ofan outer race 78 a for use in bearing assembly 74. In contrast to theearlier described embodiment, outer race 78 a does not include aplurality of tabs extending inwardly from an inner periphery 81. Aswell, second surface 49 of ledge portion 50 of chuck body 14 does notdefine a plurality of recesses. Rather than rotationally fixing outerrace 78 a to chuck body 14 with tabs and corresponding recesses,frictional forces are used to selectively fix outer race 78 a to chuckbody 14 while operating the chuck, as described below.

In operation, and referring to FIGS. 10, 11B 11C, and 12, nut grooves 62receive drive dogs 64 when the chuck is between fully opened and fullyclosed positions so that the drive dogs are adjacent groove sides 110.Inner race 72 is disposed with respect to outer race 78 a so that tabs96 and 98 are received by cam surface 106 and recess 100, respectively.That is, sleeve 18 is in the first position with respect to the nut. Inthis condition, tabs 98 and recesses 100 rotationally fix inner race 72to sleeve 18 and outer race 78 is free to rotate about body 14. Sinceinner race 72 is rotationally fixed to nut 16 by tabs 70 and flats 68,an operator rotating sleeve 18 rotationally drives the nut through innerrace 72, thereby opening or closing jaws 22. When the operator rotatesthe sleeve/bearing inner race/nut in the closing direction (indicated byarrow 90 in FIG. 10) to the point that tool engaging surfaces 43 of jaws22 tighten onto a tool shank, as shown in FIG. 9, the nut is urgedrearward up jaw threads 44, thereby pushing the nut against inner race72, bearing elements 76, outer race 78 a and thrust ring 46. Therearward force creates a frictional lock between the nut and inner race72 that further rotationally fixes two components. Additionally, therearward force increases the frictional forces between the rear surfaceof outer race 78 a and first surface 47 of ledge portion 50, in adirection opposite to the direction that sleeve 18 and nut 16 are beingrotated. Eventually, the frictional forces restrain rotation of outerrace 78 a with respect to body 14. Bearing balls 76, however, permitsleeve 18 and nut 16 to continue to rotate relative to body 14 and outerrace 78 a in closing direction 90.

The wedge between the nut threads and jaw threads 44 increasinglyresists the nut's rotation. When the operator continues to rotate sleeve18, and the resistance overcomes the hold provided by tabs 98 inrecesses 100, sleeve 18 rotates with respect to nut 16 and inner bearingrace 72. This moves drive dogs 64 from sides 110 of grooves 62 to sides108 and pushes tabs 98 out of recesses 100 into recesses 102.Simultaneously, cam surfaces 106 rotate away from tabs 96 so that thetabs are released into recesses 104, thereby engaging distal ends 88 ofpawls 86 with ratchet teeth 84, as shown in FIG. 11B. At this point,inner race 72, and therefore nut 16, is rotationally locked to outerrace 78 a, and therefore body 14, against rotation in the chuck'sopening direction. That is, the nut is rotationally locked to the chuckbody in the opening direction. Since the nut's rotation with respect tothe body is necessary to open the chuck, this prevents inadvertentopening during use.

Inner race 72, and therefore nut 16, may, however, still rotate withrespect to outer race 78 a, and therefore body 14, in the chuck'sclosing direction. During such rotation, sleeve 18 drives nut 16 throughdrive dogs 64 against groove sides 108, as well as through inner race72. This continues to tighten the chuck and, as described above,produces a clicking sound to notify the operator that the chuck is in afully tightened position.

To open the chuck, the operator rotates sleeve 18 in the oppositedirection. Sleeve 18 transfers this torque to inner race 72 at theengagement of tabs 96 and 98 in recesses 104 and 102, respectively.Because pawls 86 engage outer race 78 a, which is rotationally fixed tothe body by frictional force, through the ratchet teeth, the inner racecannot rotate with the sleeve. Thus, upon application of sufficienttorque in the opening direction, sleeve 18 moves with respect to theinner race and the nut. This moves tabs 96 back up onto cam surfaces106, thereby disengaging pawls 86 from ratchet teeth 84. Tabs 98 movefrom recesses 102 into recesses 100, and drive dogs 64 move from sides108 to sides 110 of grooves 62. Thus, the sleeve moves to its firstposition with respect to the nut, as shown in FIG. 11C, and the innerrace and nut, are free to rotate with respect to outer race 78 a andchuck body. Accordingly, further rotation of sleeve 18 in the openingdirection moves tool engaging surfaces 43 of jaws 22 away from the chuckaxis, thereby opening the chuck. As well, as nut 16 is rotated in theopening direction and rearward force on jaws 22 is relieved, thefrictional forces locking outer race 78 a to first surface 47 arereduced to the point that outer race 78 a is free to rotate about thechuck's body.

In an alternate embodiment of the chuck, inner periphery 81 of outerrace 78 a and second surface 49 of ledge portion 50 are sized such thatouter race 78 a is received about body in a press-fit. This embodimentfunctions in a manner similar to that shown in FIG. 4, and previouslydescribed. As such, a description of the operation is not repeated here.

While one or more preferred embodiments of the present invention havebeen described above, it should be understood that any and allequivalent realizations of the present invention are included within thescope and spirit thereof. Thus, the depicted embodiment(s) are presentedby way of example only and are not intended as limitations on thepresent invention. For example, an alternate embodiment of the presentinvention is shown in FIG. 13, in which a jaw 22 a includes a ridge 45 awith a tool engaging surface 43 a, wherein ridge 45 a is received in agroove 49 formed in the face of jaw 22 a. Ridge 45 a can be retainedtherein by crimping, staking, soldering, etc. An additional alternateembodiment can include a ridge that extends along the jaw face and thatis substantially parallel to the longitudinal center axis of the chuck,yet is not symmetric about a central symmetry plane of the jaw. As such,this embodiment has a tool engaging surface that is not symmetric aboutthe central symmetry plane of the jaw. It should be understood thataspects of the various one or more embodiments may be interchanged bothin whole or in part. Therefore, it is contemplated that any and all suchembodiments are included in the present invention as may fall within theliteral or equivalent scope of the appended claims.

What is claimed is:
 1. A drill chuck having a rotatable drive shaft,comprising: a generally cylindrical body having a nose section and atail section, the tail section being configured to rotate with the driveshaft and the nose section having an axial bore formed therein; aplurality of jaws movably disposed with respect to the body and incommunication with the axial bore for securing a shank of a tool in thedrill chuck, each jaw comprising: a body including a substantiallyplanar jaw face formed on an inner surface of the body and a pluralityof teeth formed on an outer surface of the body, the jaw face being bothdisposed in a first plane and parallel to a longitudinal center axis ofthe drill chuck; and a ridge depending inwardly from the first plane inwhich the jaw face lies toward the longitudinal center axis, the ridgeincluding a substantially planar tool engaging surface that is disposedin a second plane and is parallel to both the jaw face and thelongitudinal center axis, wherein the tool engaging surface is disposedcloser to the longitudinal center axis than the jaw face and only thetool engaging surface engages the shank of the tool when the tool issecured in the chuck; a nut rotatably mounted about the body such thatrotation of the nut in a closing direction moves the jaws toward thelongitudinal center axis of the drill chuck and rotation of the nut inan opening direction moves the jaws away from the longitudinal centeraxis of the drill chuck; and a sleeve rotatably mounted about the bodysuch that rotation of the sleeve in the closing direction moves the jawstoward the longitudinal center axis of the drill chuck and rotation ofthe sleeve in the opening direction moves the jaws away from thelongitudinal center axis.
 2. The drill chuck of claim 1, wherein thetool engaging surface of the ridge is symmetric about a central symmetryplane of the jaw.
 3. The drill chuck of claim 2, wherein the toolengaging surface is transverse to the central symmetry plane of the jaw.4. The drill chuck of claim 1, wherein the width of the tool engagingsurface of the ridge is between 0.020 and 0.060 inches.
 5. The drillchuck of claim 1, wherein the width of the tool engaging surface of theridge is approximately 0.032 inches.
 6. The drill chuck of claim 1,wherein the jaw face defines a groove that is parallel to thelongitudinal center axis of the chuck, the groove being configured toreceive an insert that comprises the ridge and the tool engagingsurface.
 7. The drill chuck of claim 1, wherein the chuck is configuredto receive a drill bit with a shank having a maximum diameter ofone-quarter inch.
 8. A jaw for use in securing a shank of a tool in adrill chuck having a longitudinal center axis, comprising: a bodyincluding a substantially planar jaw face formed on an inner surface ofthe body and a plurality of teeth formed on an outer surface of thebody, the jaw face being disposed in a first plane and parallel to thelongitudinal center axis; and a ridge depending inwardly from the firstplane in which the jaw face lies toward the longitudinal center axis,the ridge including a substantially planar tool engaging surface that isdisposed in a second plane and is parallel to both the jaw face and thelongitudinal center axis, wherein the tool engaging surface is disposedcloser to the longitudinal center axis than the jaw face and the ridgeextends the entire axial length of the jaw face.
 9. The jaw of claim 8,wherein the tool engaging surface of the ridge is symmetric about acentral symmetry plane of the jaw.
 10. The jaw of claim 9, wherein thetool engaging surface has a width of between 0.020 and 0.060 inches. 11.The jaw of claim 8, wherein a width of the tool engaging surface of theridge is between 0.020 and 0.040 inches.
 12. The jaw of claim 8, whereina width of the tool engaging surface of the ridge is approximately 0.032inches.
 13. The jaw of claim 8, wherein the jaw face defines a groovethat is parallel to the longitudinal center axis of the chuck, thegroove being configured to receive an insert that comprises the ridgeand the tool engaging surface.
 14. The jaw of claim 8, wherein the chuckis configured to receive a drill bit with a shank having a maximumdiameter of one-quarter inch.
 15. The jaw of claim 14, wherein the shankof the drill bit has a polygonal cross section and the tool engagingface of the chuck is configured to abut a sidewall of the shank.
 16. Thejaw of claim 8, wherein only the tool engaging surface engages the shankof the tool when the tool is secured in the chuck.
 17. A jaw for use insecuring a shank of a tool in a drill chuck having a longitudinal centeraxis, comprising: a body including a substantially planar jaw faceformed on an inner surface of the body and a plurality of teeth formedon an outer surface of the body, the jaw face being disposed in a firstplane and parallel to the longitudinal center axis; and a ridgedepending inwardly from the first plane in which the jaw face liestoward the longitudinal center axis, the ridge including a substantiallyplanar tool engaging surface and a pair of sidewalls, the tool engagingsurface being disposed in a second plane and parallel to both the jawface and the longitudinal center axis, wherein the tool engaging surfaceis disposed closer to the longitudinal center axis than the jaw face andeach sidewall is substantially planar and perpendicular to both the toolengaging surface and the jaw face.
 18. The jaw of claim 17, wherein onlythe tool engaging surface engages the shank of the tool when the tool issecured in the chuck.
 19. The jaw of claim 17, wherein the tool engagingsurface of the ridge is symmetric about a central symmetry plane of thejaw.
 20. The jaw of claim 17, wherein the tool engaging surface istransverse to the central symmetry plane of the jaw.